Method of evaluation for cooling ability of liquid
FIELD: measurement equipment.
SUBSTANCE: method is based on experimental determination of temperature of avalanching disintegration of cooling liquid on a hot surface, in static conditions, without liquid flow.
EFFECT: simplification of rejecting different lots of cooling liquid, decreasing amount of substance in investigated sample and consequently improved safety for personnel engaged in tests.
The invention relates to a method of estimating the cooling capacity of liquids and presents a way to Express control of the adequacy of the cooling capacity of the liquid for any of the developed devices using different liquids, cooling high-heat components.
There is a method of estimating the cooling capacity of liquids on a special model plants flow type. He is to simulate the flow of the liquid under study in the most tallapragada section of cooling channel cooling device (Bolshakov GF Physico-chemical principles of the use of fuels and oils. Theoretical foundations of chemmotology at. - Novosibirsk: Nauka, 1987, str-92).
The disadvantage of this method is the lack of criteria dependences satisfactorily determine the conditions of the simulation of the processes occurring in the real models. Features cooling processes depend generally on physico-chemical and operational properties of the cooler, the speed of its flow, the initial temperature and the speed of its achievements, and therefore, the chemical composition at the entrance to the considered site tract, the material flow of the channel, the means of processing and surface condition, the geometry of the heat sink surface and the nature of the flow of the coolant. Under taccom modern flowing heat exchange units is the many of the above factors are equal for various parties investigated coolant that causes fuzzy cooling capacity for various parties coolant in the field of convective heat transfer. Further heating of the test section on units flow type detects the increase of the scatter of the experimental points (for various parties coolant) depending on the wall temperature on the specific heat flow and stratification of the corresponding approximating curves, which leads to the impossibility reliable estimates of the cooling capacity of the cooling liquid.
This phenomenon is explained by the change of physico-chemical state of the fluid due to the beginning of the bubble pseudocumene, and the temperature corresponding to the beginning of the intense heat turning cooler, the so-called "destruction", the end products of which among others are solids generated during the decomposition of the cooler, and during its reaction with the impurities included in its composition. The reaction can join and intermediate products of the reactions of decomposition of the cooler. These products, which are deposited in the form of consobrina formations on the walls of the cooling tract, significantly increased thermal is soprotivlenie heat-release surface, changing as education sediment layer, its accumulation and possible entrainment by a turbulent flow. The result is overheating of the surface to be cooled and its destruction, which in turn can lead to violation of the workflow in the sample technique.
The purpose of this invention is to provide a comparative methodology for estimating the cooling capacity of liquid in stationary conditions compared with the sample fluid, the required cooling capacity is installed in field tests. Quantitative quality control of coolant on the proposed method correlates with physically reasonable value of the temperature of the beginning of intensive thermal decomposition of the coolant.
This goal is achieved by the fact that the comparative determination of the quality of the coolant is conducted on experimentally installed in static conditions, the dependency of the temperature of the heat-release surface from the time when the last temperature avalanche collapse of a cooling liquid on a hot surface, without fluid flow, in comparison with the same dependence, but for the sample of the coolant, a sufficient cooling capacity is installed.
Setup that implements the proposed method estimates the cooling capacity of the LM the bones, consists of the following main parts (see drawing):
- capacity for the analyzed fluid displacement 350 cm3designed for working pressure PP=16 MPa ("bomb"), pos.2;
- a step-down transformer for heating the experimental tube electric current, 3;
regulating transformer, pos.17,
three tanks with a volume of V=0.5 l each for filling and draining the liquid under study, pos.4,9,16;
- a can of compressed nitrogen for pressurization, pos.6.
All elements of the unit is made from a material IN, as the sealing material is a fluoroplastic-4 and aluminum. The plant is equipped with shut-off, pressure relief and drain valve.
Fuel element (experimental phase)inside the working tank and immersed in the test liquid, is heated by an alternating electric current tube diameter of 3.0×1.5 mm, and the length of the heated part 400 mm, made from steel 18CR10NITI (to study the catalytic effect of structural material for the process may use other materials and alloys). As the fuel element can also be used membrane in the measuring cell of special construction, having two cavities.
Experimental section is equipped with two thermocouples HC: on the inner surface in the center of the tube (the temperature value T2) and 4-5 mm above the outer surface of the tube, directly in the liquid (temperature T1).
The proposed method of assessment (test) quality of the coolant based on the fixing temperature increase of the inner surface of the tube by means of a thermocouple in time for xed values of electric power, providing virtually instantaneous temperature reaches the beginning of its destruction. The increase in thermal resistance, irrespective of its cause causes and the growth temperature of the inner surface of the element at a constant heat load due to the deterioration of heat exchange with the investigated liquid.
The principle of creating a test setup based on a static method, in contrast to dynamic, contributes to the solution of important problems: minimizing factors that affect the relationship heated surface-chemical conversion of fuel at high temperatures and pressures in contact with her. In traditional ("running") methods such factors very much, that does not allow us to establish the specific behavior of the actual component.
It should be noted that the proposed method comparative characterization of various parties fluids, providing a greater or lesser extent, the impact on the cooling properties, is intended to facilitate the process of rejection of various parties cooling fluid is involved in its production, storage and use. Thus, verification is the specific component composition (including microtrace), in one way or another affecting such traits as cooling capacity.
Since the proposed method is designed to generate conclusions "worse"to"better", the exact value of the temperature of the beginning of thermal decomposition does not matter, because at this stage it is not the aim of studying the process of heat exchange in the light of all history (e.g., decomposition). You only need to enter temperature mode, guaranteeing the flow of this process.
Permanently installed on-site heat load, excluding additional adjustment improves the accuracy of determining the rate of heating due to the elimination of possible methodological errors in the course of achieving a work area of the fixed temperature of the beginning of the destruction.
Thus, as the criterion (comprehensive index)characterizing OS coolant, offered the rate of internal heating surface of the heating element.
Processing of results of measurements can be carried out as follows. On the removed tape recorder is applied on scales of temperature and time scale, then set the initial "zero" time, with testwuide temperature T2. Tape recorder with 0.5 removed with the appropriate values of time and temperature T2.
The obtained temperature information (T2) and time are processed according to a special formula.
The data obtained depending on the temperature T2 higher than the temperature of thermal decomposition process by the method of least squares and obtain the parameters of the approximating straight line:
Odds are, with this method of processing the results, is the desired complex indicator of the cooling capacity of the coolant, and can be used to characterize the quality of the product.
The sequence test setting (drawing):
1. Prepare the setup for the measurements.
The original position. The source is the following
- previously, the sample fluid flushed;
- product line ready for filling;
- pressure in the system is missing;
- gearbox posr displayed;
- all valves B1-B11 are closed.
- instrumentation is disabled.
Check the tightness of the installation produced in the following order: open B6, gear P1 (POS) on the pressure gauge (POS), set the system pressure P=100 kg/cm (1.25 rrab). With closed valves B1 and B6 gauge control g is reticent exposure for 15 minutes In the presence of leaks can be checked by emiliania connection setup.
2. Refill coolant.
Checked for leaks install dressed cooling fluid through the valves B1 and B2 from the tank pos.4. Filling is as follows:
- open the valves B1, B4, B7;
- include a vacuum pump (pos.8). The system creates a vacuum (control manufacyurer POS, indications or minus 1.0 kg/cm2);
- close valve V7, open valves B3 and B2;
- after exposure installation in this state for 1 min close the valves B1, B2, B3.
3. The measurements.
The measurement is carried out in the following sequence:
- opens the valve B6 and using gear P1 is set to a pressure of 80 kg/cm2) in the vessel 5. Pressure is controlled by a manometer (POS). At the end of the pressurization valve B6 is closed:
- open valve V7;
- enabled devices KSP-4 to register the current values of the temperatures T1 and T2 (10 and 11) and time;
- batch switch on the measuring tube is the desired voltage (8 V) and current (140 A), creates a given heat load equal to 1.12 kW;
- upon reaching the temperature T2 of the temperature values of thermal properties of the investigated coolant controlled in salino by reading the respective device KSP-4, is the shutter speed for 3 seconds Recorded current and voltage in the heating tube instrument position 12 and 13,
- closes the valve V7;
- off devices KSP-4;
the heating tube is de-energised.
Measured values are the temperature of the inner surface of the heating pilot tube from the time (T2)taken from a tape recorder.
4. Return to the original position.
Return the original position is performed in the following sequence:
- opens the gate B5 and reset the pressure in the system through capacity for waste flow (pos.7) and discharge capacity (pos.9);
after reaching the measurement site temperature (20+5)°With the valve 5 closes and opens the valves B1 and B9;
- opens the valve B6 and gear P1 (POS) creates a pressure in the buffer tank (5) P=0,na;
- opens the valve V7 and the cooling liquid from the measuring node perelavlivaet in drain capacity (pos.9);
after draining component all valves are closed;
the gear P1 is displayed, the instrumentation is de-energized.
5. Neutralization product lines.
Neutralization product line is made after completion of the sample fluid and in the event of an interruption in the work on the sample more than one day
Neutralization is performed in the following sequence:
Opens the valve B6 and gear P1 (POS) creates a pressure in the buffer tank (5) P=0,mA.
Open the valves V7, B1 and B9 and is made within one minute to purge the lines with compressed nitrogen.
Produced two consecutive operations of filling and draining of the acetone from the product lines (at the above section "Filling the coolant, where the role of the valves B2 and B3 perform valves B10 and B11, respectively).
From valve 10 is detached tank with acetone and otstykovyvatsya similar capacity with alcohol.
Produced two consecutive operations of filling and draining of the alcohol from the product line.
Performed a second operation purging the lines with compressed nitrogen.
The measurement result is the dependence of the temperature on the inner surface of the heating pilot tube from time to time, removed from the tape recorder.
Implementation of the proposed method is as follows. Originally manufactured by removing the dependence of the temperature on the inner surface of the heating experimental tube over time for a sample of the coolant with the installed cooling capacity (i.e. cooling capacity which meets the requirements). Then removing the depending of the temperature of the inner surface of the heating experimental tube over time for a sample of the coolant, the cooling capacity which need to be evaluated. This is followed by a comparison of the obtained experimental data on the basis of which a conclusion is made about the suitability of the sample coolant to use.
The advantages of using this method is a simplification of the process of rejection of various parties coolant, reducing the number of substances in the test sample, which in turn ensures the safety of personnel conducting the studies, when using corrosive and toxic liquids and stores the model in the processes of heat transfer (sufficient heat to the heated fluid).
The method of estimating the cooling capacity of the liquid, in which the evaluation of the cooling capacity of the liquid is made on the basis of experimental determination of the temperature avalanche collapse of a cooling liquid on a hot surface under static conditions, no fluid flow through the comparative determining the quality of the coolant in dependency of the temperature of the heat-release surface from time to time in comparison with the same dependence for the sample of the coolant with the installed cooling capacity.
FIELD: measurement equipment.
SUBSTANCE: method for examination of thermophysical properties of liquids is proposed. It implies that a metal probe of vibration viscosity metre equipped by a temperature sensor is placed to a metal cell with a liquid sample equipped by a temperature sensor. The probe is set to harmonic vibration mode, the cell temperature is changed by a controlled cooling-heating device. Temperature, amplitude, phase and vibration frequency of the probe are measured and density, viscosity and thermal diffusivity of the liquid is determined depending on its temperature. Measurements are made to define dependency on the temperature of the liquid's optical transmission near the probe for the moments when the probe passes its equilibrium position. Device for the method implementation comprises a cell, a controlled cooling-heating device, spherical metal probe of vibration viscosity metre placed inside the cell. The probe and the cell are equipped by temperature sensors. The cell is also equipped with a fibre-optical sensor of liquid optical transmission which is set next to the probe.
EFFECT: improved accuracy of measurement.
2 cl, 2 dwg
FIELD: measurement equipment.
SUBSTANCE: substance consists in availability of a measurement device and a thermoresistive sensor of phase condition in a device for determination of phase condition of a gas and liquid flow, and the sensor comprises a printed circuit board arranged along the axis of flow movement and rigidly fixed by one short side with a sensitive element installed on it and made in the form of a substrate, on which a film resistor of the "point" design (a thermistor) is installed. The sensitive element is installed in the reference point along the vertical axis of the pipeline cross section and is connected with the measurement device, which comprises a metering circuit and a microcontroller with program control and is designed to measure variation of thermistor resistance, connected with variation of the phase condition of the medium in horizontal layers of the gas and liquid flow, and signal processing. At the same time the sensitive element of the sensor by one short side of the substrate is fixed on the edge of the short non-fixed side of the printed circuit board. The film resistor (thermistor) placed on the substrate is displaced towards the edge of the free short side of the substrate and is arranged at the distance of not more than 0.5 mm from this edge. Contact sites designed for connection of the substrate to the printed circuit board are arranged opposite to the thermistor at the opposite short side of the substrate.
EFFECT: higher efficiency of a device to determine phase condition of a gas and liquid flow.
SUBSTANCE: method for determining temperature of full polymorphous transformation of heat-resistant two-phase titanium allows of (α+β)-martensitic class is proposed, which involves preliminary preparation of a specimen by means of multistage heat treatment of the latter, which is performed immediately in a differential thermal analysis (DTA) instrument in atmosphere of cleaned argon and its investigation using DTA method. Heating of the alloy specimen to single-phase β-area, supercooling below temperatures of active diffusional decay of β solid solution, short-term exposure and repeated heating to the single-phase area is performed. Fixation of dependence of a DTA signal on temperature and calculation of values of derivative of DTA signal on temperature is performed, and temperature of completion of full polymorphous transformation is determined as per maximum on the curve of the first derivative of DTA signal at repeated high-temperature heatinge.
EFFECT: improving determination accuracy of temperature of full polymorphous transformation in heat-resistant two-phase titanium alloys.
SUBSTANCE: oil sample is heated with one-time temperature control, the sample is continuously cooled with simultaneous measurement of shear stress. Chilling point is determined from temperature corresponding to the first abrupt increase in shear stress, and bulk freezing point is determined from temperature corresponding to the second abrupt increase in shear stress. The sample is heated to temperature of 60-80°C. Heating and temperature control of the sample is carried out while revolving the viscometer cylinder and the sample is cooled at a rate of 1-2°C per minute.
EFFECT: high information value and reliability of the analysis method.
FIELD: test engineering.
SUBSTANCE: body under study is brought into thermal contact with the reference body in the plane in which the local circular heater is located. At regular intervals of time the difference of values of the temperature between the heater and the point of plane of contact of the body under study and reference body is measured. The tests end up in excess of the specified value by the controlled dynamic parameter. The dependence of the current value of thermal activity on the temperature of the body under study is made. The structural transitions in polymeric materials are determined by the presence of peaks on dependence of the current value of the thermal activity on the temperature of the body under study.
EFFECT: improved method.
SUBSTANCE: method of determining volatility and heat of vaporisation of a mixture of liquid substances from the rate of evaporation from a flat surface involves establishing a correlation relationship between volatility values, calculated using known reference data, for individual liquid substances selected as calibration liquids, and the rate of evaporation thereof, determined based on data from thermogravimetric analysis carried out in isothermic conditions when an equilibrium state is achieved. The rate of evaporation of the analysed mixture is determined and the volatility value is found from the correlation relationship. The heat of vaporisation of the mixture of liquid substances in the analysed temperature range is determined using the relationship between the found volatility values and temperature. The value of the heat of vaporisation is determined from the value of the slope of a linear graph, the abscissa of which is the value of the inverse absolute temperature and the ordinate is the logarithm of the product of the experimentally determined volatility value and the absolute temperature value.
EFFECT: high reliability and objectivity of estimating volatility of not only individual liquids, but also mixtures thereof at different temperatures, broader functional capabilities of the method of determining volatility.
2 cl, 6 dwg
SUBSTANCE: method involves separate temperature control of cylindrical samples which make up a eutectic system, one of which has the analysed composition and the other is homogeneous, for example, consists of a pure substance. The samples are brought into contact at analysis temperature which is higher than the eutectic point, and the position of imaging point of the analysed alloy relative the solidus curve is determined from the state of the liquid layer formed between the samples.
EFFECT: invention enables more accurate plotting of a solidus curve on a phase diagram.
3 dwg, 1 tbl, 1 ex
SUBSTANCE: method of determining thermo-oxidative stability of lubricating materials involves heating the lubricating material in the presence of air and mixing. Oxidised lubricating material is then collected. Oxidation process parameters are then photometered and determined using graphical curves. Two samples of the lubricating material of constant weight are tested separately with and without a catalyst. While heating, the two samples of lubricating material of constant weight are tested successively with and without a catalyst, stirred while periodically varying testing temperature from temperature at the onset of oxidation and maximum temperature. Temperature is the lowered from maximum temperature to temperature at the onset of oxidation over a constant period of time. After each testing temperature, with and without a catalyst, the samples are weighed, the weight of the evaporated sample and evaporation number are then determined as a ratio of the weight of the evaporated sample to the weight of the remaining sample. By photometering, the light flux absorption factor with and without catalyst is determined, the thermo-oxidative stability factor is determined as a sum of light flux absorption factor and evaporation number. Further, the influence coefficient of the catalyst KVK on oxidative processes is determined using the formula KVK=KK/K, where KK and K are thermo-oxidative stability factors of samples of the lubricating material with and without catalyst, respectively. A curve of the influence coefficient of the catalyst on the oxidative processes versus the testing time is then plotted, and thermo-oxidative stability of the lubricating materials is then determined from values of the influence coefficent of the catalyst on the curve. If KVK>1, thermo-oxidative stability is falling, and if KVK<1 thermo-oxidative stability is increasing.
EFFECT: high information content of the method of determining thermo-oxidative stability of oxidation and evaporation processes during periodic variation of the testing temperature.
3 dwg, 1 tbl
SUBSTANCE: proposed method consists in measuring activity of acoustic emission signals emitted by tested specimen in heating. Polymorphic transformation temperature is defined as temperature corresponding to the moment of stepwise decrease in aforesaid activity.
EFFECT: higher accuracy and efficiency.
FIELD: instrument making.
SUBSTANCE: device for determining thermal stability of substances consists of cylindrical casing filled with warmth-keeping material, in which there coaxially placed is temperature-controlled metal cylinder with cavities made along its perimetre for arrangement of tightened reaction shells each of which is connected to pressure measurement and recording system. At that, each reaction shell is equipped with flame arrester and pneumatic drive connecting the reaction shell volume to pneumatic protector and precision temperature-compensated bipolar "pressure-voltage" converter which in its turn through multi-channel analogue-to-digital converter one of the inputs of which is connected to output of "atmospheric pressure-voltage" converter, is connected to pressure display and recording system. At that, in each pneumatic drive the provision is made for the tap which is equipped with valve connected to vacuum pump with automatic valve at the inlet, inert gas source and in-series connected pneumatic resistance and valve.
EFFECT: invention allows shortening the time and measurement period, calibration intervals, improves reliability at reducing overall dimensions and electric power consumption.
2 cl, 1 dwg
FIELD: investigating or analyzing materials.
SUBSTANCE: thermograph comprises differential thermocouple and aluminum thermal unit provided with two symmetrically arranged cylindrical holes for crucible with specimen and standard. The crucibles are made of cylinders with caps provided with copper pipes for hot junctions of Chromel-cupel thermocouples. The wires of the thermocouples are housed in the two-channel ceramic rods. The thermoelectric heating of the unit is provided with the use of temperature-sensitive resistor made of nichrome wire. The unit is mounted in the steel sealed housing with a lid and provided with a device for locking it inside the housing during cooling and heating.
EFFECT: simplified design and enhanced accuracy of measuring.
FIELD: polymorph processes in metals and electro-conducting materials.
SUBSTANCE: method of measuring temperature of polymorph transformation is based upon heating for hardening till temperature providing free sag of rigidly tight sample. The temperature should correspond to α→β polymorph transformation.
EFFECT: improved precision of measurement.
FIELD: measurement technology.
SUBSTANCE: device has trier provided with holder and measuring probe provided with thermocouple placed inside the trier. Thermocouple is used which has time constant less than 1,5 sec. Volume of part of thermocouple submerged into salt melt relates to volume of cup of the trier as (5x10-3-10-2):1. Precise value of temperature can be achieved as well as high degree of reproducibility.
EFFECT: improved precision; prolonged service life of thermocouple.
9 cl, 4 dwg
FIELD: test equipment.
SUBSTANCE: metal probe of vibration viscosimeter is disposed inside metal dish in tested fluid to make it thermally isolated from outer space. Viscosimeter is excited with preset frequency and with preset force. Temperature of the dish is changed monotonously and continuously to follow specified rule at speed to exceed speed of establishing processes of change in temperature of tested liquid inside the dish. Temperature of the probe is measured within whole preset range of changes in temperature of the dish as well as amplitude and/or phase and/or frequency of oscillations of the probe. Density, viscosity, thermal conductivity, heat capacity and thermal diffusivity of tested fluid are measured depending on fluid's temperature from the relation of heat diffusivity of fluid and from the relation of viscosimeter's probe forced oscillations. The main feature of the device realizing the method has to be the metal probe of viscosimeter made in form of copper ball or silver ball disposed in fluid for thermal insulation onto rod made of thermo-insulating material. Measuring converter of probe's temperature is made in form of thermocouple and built inside probe. Second measuring converter of probe's temperature, also made in form of thermocouple, is placed onto bottom of metal dish thermally insulated from environment.
EFFECT: improved efficiency of test.
10 cl, 5 dwg
FIELD: inspection of quality of oil products.
SUBSTANCE: permanent-weight lubricant is subject to heating in thermo-stable glass cup at three temperatures at least, which temperatures exceed that one of beginning of oxidation and then it is subject to mixing by glass mixer at constant speed during 12 hours or less. Samples for photometry are selected in equal time intervals. Factor of absorption of light flux by oxidized oil Ability to evaporation is measured by weighing sample before and after test. Graphical dependences of theses parameters are built relatively temperature of testing. Thermal-oxidative stability of lubricant is determined by critical temperature of service ability, by temperature of beginning of oxidation and by temperature of beginning of oxidation.
EFFECT: improved efficiency of measurement.
FIELD: investigating or analyzing materials.
SUBSTANCE: method comprises heating specimens to be analyzed with a rate of 10 deg/min, using standard initial polymineral clays, selecting temperature intervals 20-200°C, 600-800°C, and 20-100° C from the thermo-analytic curves of the standards, determining the reference values in the intervals, determining mass losses, and choosing maximum values of the mass losses in the intervals for the calculation of the fraction ration of clays.
EFFECT: enhanced accuracy of measurements.
6 dwg, 1 tbl, 6 ex
FIELD: measurement technology.
SUBSTANCE: method involves carrying out experimental temperature measurements of cooling liquid avalanche dissociation on hot surface under static conditions, without liquid flow being arisen.
EFFECT: simplified cooling liquid quality control process; reduced tested substance quantity in samples under test; personnel safety in carrying out tests.
FIELD: measuring technique.
SUBSTANCE: method comprises testing two samples of the lubricant of the same mass, the first sample being tested without catalyzer and the second sample being tested in the presence of catalyzer, determining transparency coefficient by means of photometric measurements, plotting time dependences of the transparency coefficient, and determining oxidation stability of the lubricant from the equation presented.
EFFECT: enhanced precision.
3 dwg, 1 tbl
FIELD: measuring technique.
SUBSTANCE: while warming sample up, average value of square of voltage of thermal electrical; fluctuations is measured at terminals of measuring converter. Maximal value, which corresponds to glass transition temperature, is measured, at which temperature the value of dielectric permeability is found and value of hardness coefficient is calculated. Method can be used for measurement of equilibrium hardness coefficient of polymer chains for polymers in unit.
EFFECT: improved precision of measurement.
1 dwg, 6 tbl
SUBSTANCE: method provides usage of temperature detectors to transform electric signal, and identification of type of phase transition. Electric Signal from temperature detector is corrected for value of electric signal which is generated by phase transition of material. Correcting electric signal is achieved by means of additional probe.
EFFECT: improved precision of measurement.
4 cl, 9 dwg